The present invention relates to an image pick-up module and, in particular, to an image pick-up module with a lens and image pick-up semiconductor chip integrally incorporated in one package.
In recent years, a growing demand has been made for a compact image sensor in various kinds of multimedia fields and for devices including information terminals, such as a monitor camera, tape recorder. As a compact type image sensor unit suitable to this kind of image input devices, there is an integral unit package with a solid-state image pick-up element, lens member, filter, stop member, etc., incorporated therein.
In a conventional sensor unit, after a solid-state image pick-up element has been mounted on a substrate, the substrate is joined to the package with the use of screws, bonding, etc., while, on the other hand, a support frame with a lens member held thereon is mounted on the package. Due to such a structure, no adequate accuracy has been abled to be secured for the positional relation of the lens to the solid-state image pick-up element.
In the conventional sensor unit, the positioning accuracy of the lens relative to the solid state image pick-up element was poor and, therefore, a movable focus adjusting mechanism was incorporated into the package for focus setting and, after the assembly of each component part into the package, the focus setting was made by the focus adjusting mechanism relative to the solid image pickup element.
However, a focus setting operation, that is, the operation of the movable adjusting mechanism after the assembly of each component part, was separately necessary. Further, after such a focus setting, the fixing operation of the lens frame member, etc., was necessary. Since the movable type focus adjusting mechanism is provided, a resultant structure becomes complicated and there was a tendency that the sensor unit become bulkier.
Further, during the focus setting operation, dirt and dust are liable to intrude into the unit via a clearance at a movable section of the focus setting mechanism and the countermeasure is necessary, such as the focus adjusting operation has to be done in a cleaning room, and a poor production results. The movable type focus adjusting mechanism is liable to suffer a vibration, shock, etc., so that a focus setting position is liable to be deviated. This involves a disadvantage of being poor in product reliability.
JPN PAT APPLN KOKAI PUBLICATION NO. 9-232548 has proposed a solid-state image pick-up device of such a structure as to enable a positional accuracy of a lens relative to a solid-state image pick-up element in an optical axis direction to be secured. The solid-state image pick-up device has one support member with a plurality of positioning sections provided in a stepped fashion. In this case, component parts such as a solid-state image pick-up element, lens member, filter, stop member, etc., are individually separately mounted on the corresponding steps and these members are positioned and fixed. As a result, the dimensional error among the respective steps exerts a greater influence on the positioning accuracy of each member.
Forming these positioning sections in the stepped fashion on the support member offers a difficulty in managing the dimensional accuracy and is liable to introduce an error. Further, a higher degree of production technique is required in forming a plurality of such positioning sections on one support member. In the case where the support member is formed with the use of ceramics material, the manufacture is very difficult and at high costs.
It has been considered that, in most cases, such a support member is manufactured by injection-molding a material such as a synthetic resin.
Even if the support member is manufactured with the use of the injection mold, a resultant product is liable to produce a greater dimensional error among the positioning sections composed of the stepped sections. Further, it has been considered that errors are developed due to the aging and that the product obtained involves a poor reliability.
As set out above, in the conventional solid-state image pick-up device, dimensional errors are liable to be produced among the respective positioning sections and their dimensional control is difficult and no adequate positional accuracy can be secured in the optical axis direction of the lens relative to the image pick-up element. The structure obtained is complicated, poor in productivity, high in manufacturing costs and high in product costs.
It is accordingly the object of the present invention to provide an image pick-up module which improves the mounting accuracy of a lens member relative to a solid-state image pick-up element in an optical axis direction, obviates the need to provide a focus setting adjustment mechanism, is simpler in structure and less in number of component parts involved, improves an assembling operation, size reduction of a product and product reliability, and is low in cost.
In order to achieve the above-mentioned object, the invention of claim 1 is directed to an image pick-up module comprising an image pick-up lens member; a lens frame member retaining the lens member; a semiconductor circuit section having a photoelectric conversion section comprised of two-dimensionally arranged photoelectric conversion element groups, a drive circuit section sequentially driving the photoelectric conversion elements and obtaining a signal charge, an A/D conversion section converting the signal charge to a digital signal, a signal processing section outputting the digital signal as a video signal, light exposure control means electrically controlling a light exposure time based on an output level of the digital signal, the photoelectric conversion section, drive circuit section, A/D conversion section, signal processing section and light exposure control means being formed on the same semiconductor chip; a substrate holding the semiconductor chip 1 and having electrode groups electrically connected to the semiconductor chip;
a frame member for covering which is connected to the substrate and has a hollow structure covering the semiconductor chip; and
an infrared ray shutting optical member mounted on the frame member, in which
on one surface of the substrate, a positioning reference surface P constituted of an equally flattened surface is defined up to an outer peripheral end of the substrate, the positioning reference surface P includes a semiconductor chip positioning reference surface portion at which the semiconductor chip is joined in a planar way and positioned, a frame member mounting surface portion situated around the semiconductor chip and at which the frame member is joined and mounted, and a lens frame positioning reference surface portion situated outside the frame member and left as a remaining portion at the outer peripheral end portion of the positioning reference surface P and at which the lens frame member is joined upon being mounted and positioned, and in which the semiconductor chip and lens frame member are positioned on the positioning reference surface constituted of the equally flattened surface defined on the one surface of the substrate while using the semiconductor chip positioning reference surface portion and lens frame member positioning reference surface portion.
The invention of claim 2 is directed to an image pick-up module comprising:
an image pickup lens member;
a lens frame member retaining the lens member;
a semiconductor circuit section having a photoelectric conversion section comprised of two-dimensionally arranged photoelectric conversion element groups, a drive circuit section sequentially driving the photoelectric conversion element groups and obtaining a signal charge, and an A/D conversion section converting the signal charge to a digital signal, the photoelectric conversion section, drive circuit section and A/D conversion section being formed on the same semiconductor chip; and a substrate 2 retaining the semiconductor chip and having electrode groups electrically connected to the semiconductor chip, in which, on one surface of the substrate, a positioning reference surface P comprised of an equally flattened surface is defined, the positioning reference surface P includes a semiconductor chip positioning reference surface portion at which the semiconductor chip is joined in a planar way and positioned and a lens frame positioning reference surface portion situated around the semiconductor chip and left as a remaining portion at the outer peripheral end portion of the positioning reference surface P, and at which the lens frame member is joined upon being mounted and positioned, and in which the semiconductor chip and lens frame member are positioned on the positioning reference surface P constituted of the equally flattened surface defined on the one surface of the substrate while using the semiconductor chip positioning reference surface portion and lens frame member positioning reference surface portion.
An image pick-up module of claim 3 incorporates, into a semiconductor circuit section of the image pick-up module of claim 2, a signal processing section outputting the digital signal as a video signal and light exposure control means electrically controlling a light exposure time on the basis of an output level of the digital signal.
An image pick-up module according to claim 4 is characterized in that an optimal member is assembled in an air-tight state in the lens frame member to provide the lens frame member as a hermetic structure and a joined section between the lens frame member and the reference surface is sealed, and the semiconductor chip is sealed with the lens frame member.
An image pick-up module according to claim 5 is characterized in that an optical member, such as an infrared ray shutting member or lens or optical window member is assembled in an air-tight state on the lens frame member to provide a lens frame unit and a joined section between the lens frame unit and the reference surface is sealed in an air-tight fashion and the semiconductor chip is sealed with the lens frame member.
An image pick-up module according to claim 6 is characterized in that a dust-tight transparent member is arranged outside the lens frame member to provide an air-tight structure and a surface joined to the reference surface is sealed and the semiconductor chip is sealed with the lens frame unit.
An image pick-up module according to claim 7 is characterized in that the optical member assembled on the lens frame member recedes to a position more away from the semiconductor chip than an inner wall surface of the lens frame member facing the semiconductor tip and is located within a thickness range of the optical axis direction of the wall section of the lens frame member.
An image pick-up module according to claim 8 is characterized in that the substrate is comprised of a bulk ceramics substrate.
The image pick-up module according to claim 9 in which the positioning reference surface is wholly formed up to an outer peripheral end of the substrate and electrode groups are located at the outer end portion of the substrate.
The image pick-up module according to claim 10 is characterized in that, at one end of the lens frame member facing the positioning reference surface, abutting projections are provided which abut against the positioning reference surface except at the electrode groups of the substrate and recesses are provided in those positions facing the electrode groups and astride and away from the electrode groups.
The image pick-up module according to claim 11 is characterized in that the lens frame member is fitted over the outer periphery of the frame member; at that fitting section between the frame member and the lens frame member, projections are provided at one of the frame member and lens frame member to allow the projections of the one member to be joined to the other member; and the frame member and lens frame member are positioned by the projections and a clearance is formed between the frame member and the lens frame member.
The image pick-up module according to claim 12 is characterized in that the infrared ray shuttering optical member is comprised of a multi-layered type infrared ray elimination filter.
The image pick-up module according to claim 13 is characterized in that a stationary stop aperture is provided at the forward end portion of the lens frame member.
The image pick-up module according to claim 14 is characterized in that, at the forward end portion of the lens frame member, a cylindrical wall is provided around the stop aperture.
The image pick-up module according to claim 15 is characterized in that a protective coating film is coated on the electrode groups at least at these portions where other members are joined.
The image pick-up module according to claim 16 is characterized in that the electrode groups are provided at the positioning reference surface of the substrate except at an area where the electrode groups are joined.
The image pick-up module according to claim 17 is characterized in that no coating is made at that area of the electrode groups corresponding to the recess.
According to the invention according to claims 1 to 3, the mounting positions of the semiconductor chip and lens frame member are determined on the positioning reference surface of an equally flattened surface defined on one surface of the substrate and it is possible to enhance the positional accuracy of both while adopting a simpler structure. The positioning is completed unconditionally by assembling the semiconductor chip and lens frame member on the same substrate. And the post-assembling focus setting is not necessary and it is possible to make an assembly in a simpler and readier way. Since the positioning accuracy of both the semiconductor chip and lens frame member are enhanced, it is not necessary to provide a focus-setting movable adjusting mechanism which would be required in the prior art. The resultant structure is less in the number of component parts required, compact, lightweight, lower in costs, etc. Further, it is possible to prevent the generation of an error resulting from the movable adjusting mechanism as well as a lowering of reliability. It is also possible to enhance the resistance to vibration. Further, the image pick-up module obtained is simple and high in air-tightness and it can be used even under a severe environment of use.
In the present invention according to claim 2, the semiconductor circuit section formed on the semiconductor chip includes an A/D conversion section for converting a signal charge which is obtained from the photoelectric conversion section to a digital signal and the electric image pick-up processing is completed. According to claims 1, 3, the semiconductor circuit section formed on the semiconductor chip includes an A/D conversion section for converting a signal charge which is obtained from the photoelectric conversion section to a digital signal and a light exposure control means for electrically controlling a light exposure time on the basis of an output level of the digital signal. Even if any mechanical stop mechanism is not incorporated for light amount control, an image pick-up function is completed and the mirror body of the image pick-up module is made simple and lightweight.
In the invention according to claims 2, 3, 4, 5, 6, 7, it is possible to, without providing any frame member, obtain a simple structure less in the number of component parts required, hermetically seal the semiconductor chip and secure product reliability. Further, by reducing the component parts required, the structure can be made lightweight, smaller in size and lower in manufacturing costs. Further, since the lens frame member is utilized as a hermetically sealed member, a sealing-only member is not required and a larger semiconductor chip can be held within a restricted space and a compact size can be obtained. Further, since the infrared ray cut filter, etc., arranged at the forward end side of the optical system is also used as a sealing member, it is equipped with a water-tight function.
Further, in the image pickup module according to claim 7, the optical member assembled on the lens frame member is arranged in a thickness range of the wall section of the lens frame member, thus obtaining a compact unit.
In the invention according to claim 8, the positioning reference surface is obtained with high accuracy and the image pick-up module can be manufactured at low costs.
According to the present invention of claim 9, the electrode groups can be rationally arranged on a single substrate.
According to the present invention of claim 10, the lens frame member does not hit directly against the electrode groups provided on the substrate. And the electrode group is protected and the positioning of the lens frame member is secured. Upon soldering, heat exerts a minimally possible small influence on the lens frame member.
According to the invention of claim 11, the positioning accuracy of the lens frame member relative to the frame member is enhanced and the fixing of both is positively secured and, upon soldering, heat exerts a minimally possible low influence on the lens frame member. Further, for example, the lens frame member can be bonded to the frame member through the utilization of the clearance.
According to the invention of claim 12, reliability is improved in terms of an optical function.
According to the invention of claim 13, the positioning accuracy of the lens frame member relative to the semiconductor chip is high and, as the stop, a stationary stop aperture well serves that purpose. This stop structure is simpler and smaller in size. Since, in particular, the xe2x80x9cstopxe2x80x9d section is provided at the forward end side of the image pick-up structure, a simpler mold, etc., can be used and a protective function, etc., can be obtained at the forward end side of the lens.
According to the invention of claim 14, it is possible to prevent a damage to the stop aperture.
According to the invention of claim 15, any inconvenience, such as the electric short-circuiting, resulting from the joining of the electrode groups can be avoided.
According to the invention of claim 16, the inconvenience of joining the electrode groups to the lens frame member is avoided and the positing accuracy of the lens frame member can be secured.
According to the invention of claim 17, no coating is required at the area of the electrode groups, so that it is possible to simplify the structure and to improve the productivity.